The present invention relates to an image forming apparatus such as an electrophotographic copying machine and a printer, in which a plurality of toner images having different colors are successively formed on a photosensitive drum, and a plurality of toner images formed on the photosensitive drum are transferred to a transfer member carried on a transfer drum under such a condition that these plural toner images are successively overlapped with each other, to thereby form an image. More specifically, the present invention relates to a technique for stripping (exfoliating) the transfer member carried on the transfer drum.
Conventionally, as an image forming apparatus using this sort of transfer drum, there is an image forming apparatus in which a plurality of toner images having different colors such as cyan, magenta, yellow, and black are successively formed on a photosensitive drum, and then the plural toner images formed on this photosensitive drum are transferred to a transfer member such as a transfer paper carried on a transfer drum under such a condition that these toner images are successively overlapped. Then, in this image forming apparatus, after a predetermined member of toner images attracted on the transfer drum have been transferred onto the transfer member in the multiple mode, this transfer member is stripped (exfoliated) from the surface of the transfer drum, and then the toner image is fixed on the transfer member by way of a fixing device. At this time, in order to firmly strip the transfer member from the surface of the transfer drum, such a stripping (exfoliating) apparatus as a stripping finger whose tip portion is made sharp is used in this image forming apparatus.
For instance, as shown in FIGS. 19 to 21, as this stripping apparatus, the stripping finger 100 made of the plate-shaped metal member whose width is made narrow is made in contact with the transfer film 101 for forming the surface of the transfer drum at a predetermined timing, and the tip portion of the stripping finger 100 is made sharp. After the transfer member 102 is stripped from the transfer film 101 by way of the sharp tip portion of the stripping finger 100, the transfer member 102 is lift up by the upper surface of the stripping finger 100, so that the transfer member 102 is stripped from the surface of the transfer drum (disclosed in Japanese Laid-open Patent Application No. Hei. 1-254,986). Also, in the above-described stripping apparatus, to assist the stripping effects of the stripping finger 100, a plurality of stripping guide members 103 are arranged at both sides of the stripping finger 100, which may float the transfer member 102 stripped from the surface of the transfer drum by this stripping finger 100. Then, these plural strip guide members 103 are fixed to the supporting member 104 in an integral form of the stripping finger 100. This supporting member 104 is pivoted at a predetermined timing, so that the tip portion of the stripping finger 100 is made in contact with the surface of the transfer film 101.
However, in the case of the above-described conventional image forming apparatus, since a plurality of strip guide members 103 are pivoted in conjunction with the stripping finger 100, the strip guide members 103 would approach to the transfer drum up to the unwanted distance when the stripping finger 100 picks up the transfer member 102. Therefore, when the stripping fingers 100 pick up the transfer member 102, the positions of the strip guide members 103,103, - - - , are defined to the positions for avoiding interference with the transfer drum. In other words, if the strip guide member 103 is set to the position for avoiding interference with the transfer drum when the stripping fingers 100 pick up the transfer member, the strip guide member 103 is returned to the original position after the stripping fingers 100. When the transfer member 102 is picked up by the strip guide member 103, the tip portion of the strip guide member 103 has passed the upper side of the transfer member 102, and thus this transfer member 103 is not picked up. Therefore, there is a problem that a jam happens to occur.